The Earth’s Spherical Coordinate System
This lesson is developed as practical exercise to help learn about coordinate systems and graphing. It also introduces students to various projections
of spherical coordinates onto a plane. The Earth’s coordinate system (from http://gis.washington.edu/esrm250/lessons/projection/)
parallels of latitude (Y)
meridians of longitude (X)
Combined Coordinate System
Note that the Prime Meridian goes through
England.
1
To become familiar with this system, cut out the pattern below and glue it to a tennis ball.
Place these labels on the parallels: 60N, 30N, 0, 30S, 60S, and these on the meridians: 0, 30W, 60W, 90W, 120W, 150W, 180, 150E, 120E, 90E, 60E, 30E.
2
In order to make a map of the world, the coordinate system must be distorted.
Converting to a planar map is often called “projection”
because projecting from within the Earth to a shadow cast
upon a surface located around the earth is one possible
means of mapping.
In the case of the projection on the right, the north and
south poles would be located at infinity!
This type of projection is called cylindrical.
3
The Mercator projection is a type of cylindrical
projection. Meridians are parallels are drawn every 30
degrees on this example. Note how distorted the sizes of
the land masses are near the poles. Greenland is 1/8th the
area of South America but appears to be larger!
The Robinson projection has less distortion of the size of each region.
4
5
For practice using the coordinate system, plot the locations of the largest earthquakes since 1900 on both your globe and on the Robinson projection.
Location
1.
Chile
2.
Prince William Sound, Alaska
3.
Off the West Coast of Northern Sumatra
4.
Kamchatka
5.
Off the Coast of Ecuador
6.
Northern Sumatra, Indonesia
7.
Rat Islands, Alaska
8.
Andreanof Islands, Alaska
9.
Assam - Tibet
10.
Kuril Islands
11.
Banda Sea, Indonesia
12.
Kamchatka
Updated 2006 January 25
Date
1960
1964
2004
1952
1906
2005
1965
1957
1950
1963
1938
1923
UTC
05 22
03 28
12 26
11 04
01 31
03 28
02 04
03 09
08 15
10 13
02 01
02 03
Magnitude
9.5
9.2
9.0
9.0
8.8
8.7
8.7
8.6
8.6
8.5
8.5
8.5
Coordinates
38.2S
61.0N
3.30N
52.8N
1.0N
2.1N
51.2N
51.6N
28.5N
44.9N
5.05S
54.0N
73.1W
147.7W
95.8E
160.1E
81.5W
97.0E
178.5E
175.4W
96.5E
149.6E
131.6E
161.0E
References:
http://gis.washington.edu/esrm250/lessons/projection/
6
To become familiar with this system, cut out the pattern below and glue it to a tennis ball.
Place these labels on the parallels: 60N, 30N, 0, 30S, 60S, and these on the meridians: 0, 30W, 60W, 90W, 120W, 150W, 180, 150E, 120E, 90E, 60E, 30E.
7
The Robinson projection has less distortion of the size of each region.
8